Combination flexible coupling and torque control



April 1935- G. TREMOLAIDA I 1,996,311

COMBINATION FLEXIBLE COUPLING AND TORQUE CONTROL Filed Feb. 3, 1935 3 Sheets-Sheet l 4 I ZZ.\56 4 [/v vg/v 7-02.- Guy //'e no Tremo/adcz 6r ad A TTORJiEK April 2, 1935. G. TREMOLADA COMBINATION FLEXIBLE COUPLING AND TORQUE CONTROL Filed Feb. 3, 1933 3Sheets-Sheet 2 April 2, 1935. TREMOLADA 1,996,311

COMBINATION FLEXIBLE COUPLING AND TORQUE CONTROL Filed Feb. 5, 1953 3 Sheets-Shest 3 [/v v/v 70a Y86149019 /mo Tre rrzo/qala Arroexvax synchronous speeds.

Patented Apr. 2, 1935 UNITED STATES PATENT OFFICE .COIWBINATION FLEXIBLE COUPLING AND TORQUE CONTROL California.

Application February 3, 1933, Serial No. 655,037

11 Claims.

, which can be transmitted from the drive to the driven device, which includes flexible coupling features in order that the same be adapted for connecting together a drive and a driven shaft, and includes shock absorbing features in order that when starting the apparatus or when placing a load on the driven device of the apparatus this device of my invention will relieve the shock by absorbing the torque until such a time that the drive and driven devices are operated at It will be understood, however, that these various parts of my invention may be separately used as desired and therefore my invention comprehends a device which acts as a torque control, or a device which constitutes a flexible coupling, or a device which constitutes a shock absorber. I believe my invention not only to be broadly new in'its entirety, but believe the various elements and subcombinations of the invention in its entirety are new and therefore seek patent protection on the invention in its entirety and in its several cooperating parts.

My invention has a particular utility in operating oil well pumps in the oil producing industry, and in view of this fact I will describe that embodiment of my invention which I have designed particularly for this use. It should be strictly understood, however, that my invention maybe employed in the various arts and industries where control apparatus of the general type of my invention has a utility, and it should likewise be understood that I do not wish to limit my invention to the oil producing industry. I am describing this particular embodiment of my invention merely for the purpose of instructing those skilled in the art as to how my invention may be practiced.

In order that the features of my invention may be more readily understood, I will make brief reference to that portion of the oil producing in- E; dustry to which my invention appertains. For

' been found highly desirable and economical to operate the pump relatively slowly and with a relatively long stroke, and it is the practice at the present time to employ a reduction gear drive means which permits the use of a prime mover of a relatively low horsepower. The type of reduction apparatus which may be employed with considerable success in the practice of my invention is the Falk speed reducer, such as the SDA type manufactured by The Falk Corporation, Milwaukee, Wisconsin. The speed reduction unit, to which I refer as the driven device or the driven means in the ensuing part of my application, may be operated by a small motor or gas engine of relatively low horsepower, which apparatus performs highly satisfactorily so long as operating conditions of the apparatus remain at, or nearly at, normal. Whenever an abnormal condition exists, the drive means, which may be the motor or gas engine, may be unduly taxed and injury thereto may result; or the driven means may be injured by being operated while some abnormal condition prevails; for example, there may be a breakage of a part, there may be a freezing of a bearing, there may be slippage of belt drives, or the oil pump operated thereby may be sanded up. When the term abnormal condition is referred to, it is meant that some condition is brought to pass in the apparatus which increases the driving torque necessary to operate the apparatus, and thus produces greater strain on the drive means.

It is an object of my invention to provide means which automatically shuts down the drive means or prime mover when the torque required to 0perate the driven means becomes abnormal.

Another object of my invention is to provide a torque control means which moves into a predetermined position when the torque becomes abnormal. When such means moves into a. predetermined position, it may, as will be fully described hereinafter, operate the apparatus whereby the drive means is deenergized.

A still further object of my invention is to so design the torque control means that, during the starting of the apparatus when the starting torque is in effect, which starting torque is considerably greater than the normal operating torque, it will permit the drive means to operate the driven means during a starting of the apparatus without the apparatus shutting off. other words, when such apparatus is started it is necessary to transmit from the drive means to the driven means an excessive torque until the driven means has been brought to normal V and driven means.

operating speed and the torque reduced to normal operating torque.

' In the preferred form of my invention I accomplish this result by providing the device of my invention with a positive driving means which comes into operation when an excessive or large amount of torque is applied through the device of my invention.

A still further object of my invention is to provide a torque control means in which the parts return to normal position when the torque be tion, there is considerable shock imposed upon theparts-of the driven means and the transrnitting-devices connected between the drive and driven means if the parts are rigidly connected together.

' It is an object ofmy present invention to providea shock absorbing means which may be incorporated in the power transmitting device located between the drive and driven means, which will absorb the shocks and thus reduce the strains placed on the mechanism.

e In the-preferred form of my invention I provide a structure in which one part rotates relative'to the other and in which the torque is gradually transmitted from the drive means to the driven means and the driven means graduallybrought up to normal speed. When the driven means is driven at normal speed, the

torque required to drive same naturally reduces andas this -reduction in driving torque occurs, the parts constituting my invention gradually returnto normal positions to occupy these normal positions until'an abnormal torque condition occurs.

-My invention, as previously pointed out, may embody one or more of the objects which have been outlined heretofore. preferred form includes each and everyobject but, as will be seen from the foregoing explana- 7 forms of my .invention'in detail.

tion of theobjects'of my invention, these various objects may be independently usedif the features of my invention in their entirety are not desired; This point is rather important and shouldbe kept in mind when considering the scope and nature of my invention.

Iwill now refer to the drawings in which my invention is illustrated and will describe various During the course of this description, various important features? and advantages of the invention will be brought out. v V 1 In the accompanying drawings,

Fig.1 is a diagrammatic .view illustratingth utility of one formof my invention, certain portions of the apparatus being shifted from their normal relative position in this view to effect sim- V plicity of illustration. 2

Fig. 2 is a'section of the form'of invention whose utility is disclosed in Fig. 1.

' Figsp3 and 4 are sections taken as indicated by the lines 33 and i-t of Fig. 2.

My invention in' its- Fig. 5 is a sectional view similar to Fig. 2 but showing the form of my invention which is designed primarily for use as a shock absorber.

- Fig. 6 is a section through a device of my invention which is designed for use where a belt or chain drive isemployed.

Fig. 7 is a section taken on the line 'I-'l of Fig. 6.

I will now refer to Figs. 1 to 4 inclusive and describe the details of construction of thefirst form of my'invention.

As shown in Fig. l, the numeral H represents a drive means which may be any type of prime mover or driving mechanism. The numeral l2 represents a driven means which may be any type of apparatus which is driven by a drive means for any useful purpose. In the illustration in Fig. l,'the drive means l: is an electric motor and the driven means i2 is a Falk speed reducer of the 5DA type manufactured by The Falk Corporation,- Milwaukee, Wisconsin; The speed reducer has a shaft 5 to-which a crank i5 is connected. This crank I5 is in turn connected to the lower end of a pitman it. The pitman [6 re ciprocates a walking-beam El and the walkingbeam ll reciprocates a string of sucker rods l8 which'is connected thereto. Connected to the lowerend of the string of sucker rods I8-is a pump plunger it which is finally reciprocated to pump oil to the surface of the ground. The drive means has a drive shaft 26 which constitutes a part of a drive element, and the speed reducer i2 has a driven shaft 2! which constitutes a part of a drivenelement.

tion. Reference will now be had to Figs. 2 to 4 inclusive in order that the details of construction of this form of my invention may be understood. Thedrive shaft 26 is provided with a sleeve 23 which is rigidly securedthereto by use of a suitable key 24 and by use of a setscrew 25. This sleeve 23 has an outer cylindrical surface 23, as shown. Adapted to be supported thereon is a section member 28 of a coupling member 29 which constitutes .a part of the coupling means of my invention. The coupling member 29 is therefore, rotatably, as well as slidably, supported by the cylindrical surface 23 of the sleeve 23 and'is, therefore,'rotatab1y, as well as slidably, supported relative to the drive shaft 29. The leftward end of the sleeve 23 is provided with a series of splines 36 which are arranged at an angle to the axis of rotation A-A' of the parts. These splines 33 are adapted to extend into slots or keyways' Connected to these drive and driven shafts 2B and 2! is a control device '22 which incorporates the features of my inven- 3i provided in the leftwardend of the section V tion indicated by the arrow 33 whena relative" rotation occurs between the drive shaft 20 and the coupling member 29. The drive shaft 26 is driven in a direction indicated by the arrow 34 of Fig. 2 and it will, therefore, be seen that there is atall times a tendency for the splines 3%? to engage the walls of the slots- 3! and to produce a reactionary force which tends 'at all times to move the coupling member 29 in thedirection indicated by the arrow 33.

. Secured to the section 28 is a section 35 which is in alignment therewith. Positioned between the sections 28 and 35 is a thrust plate 3%, there being bolts 3'! for'securingthese parts together. The Section '0! the 6013311118 29 surrounds the driven Shaft II and is internally threaded at 38 so as to adjustably' a nut 39. Mounted on the driven shaft 2 eitherrigidly or adjustably, is a collar 40. There is, however, a key 4| which prevents relative rotation between these parts even though one part might be slidable relative to the other. The oolhr has on therightward end thereof a series of teeth or blades "which are arranged in cylindrical order as disclosed best in Fig. 3. interior of the section 35 is provided with inwardly extending blades or teeth 43, and these blades of teeth 42 and 43 coengase with each other in order that there may be a driving engagement between the coupling member 29 and the driven shaft 2|. The blades 42 and 43 are at angles relative to the axis A--A, but it will be noticed that they are angled oppositely to the splines 30 and the slots 3|. The blades 42 and 43 are so disposed that when the coupling member 29 drives the collar 49 a reactionary force is produced which tends to force the coupling member in the direction of the arrow 33. This is done in order to reduce any friction which might restrain the' collar member from moving in a rightward direction in response to the reactionary force produced by the splines 33 and the walls of the slots 3| when a certain amount of driving torque is transmitted.

The collar 43 is provided with a shoulder 45, and compressed between the shoulder 45 and a bearing 46 which engages the nut 39 is a compression spring 41. This compression spring exerts a force which at all times tends to maintain the coupling member 23 in the position in which it is shown in full lines in Fig. 2. When torque is transmitted through the apparatus there is a tendency for the spring to compress and when the torque transmitted thereto increases above a certain amount, the coupling member 29 will move in the direction of the arrow 33. d r

The thrust plate 36 has an inwardly extending'flange 49 which is adapted to engage a shoulder 50 provided by the end of the sleeve 23 when the coupling member has moved in the direction of the arrow 33 a predetermined distance and when the parts have moved into a position indicated by dotted lines 5| of Fig. 2. When the parts have moved into these positions there is a positive driving engagement between the drive and driven shafts 20 and 2|. This is a feature which enables the drive means to drive the driven means with an excessive starting torque until such time that the driven means is operating at normal speeds and until such times as the torque reduces to normal. The parts remain in dotted line position until the torque returns to normal at which time the parts return to normal position, as shown by full lines in Fig. 2.

In view of the fact that it is exceedingly difiicult, if not impossible, to establish and maintain a true axial alignment of the shafts 23 and 2| along the axis A-A, I find it highly desirable to incorporate as a part of my invention a flexible coupling feature which compensates for any angular disalignment. This portion of my invention I will now describe.

Supportedby the end of the shaft 20 or by the sleeve 23 is a block 54 having a-seat 95 of spherical character. Supported by theshattZi or by the collar 40 is aseco'ndblock 96 which has a spherical seat 51. These spherical seats are arranged concentric tothe axis of each of the shafts 23 and 2|. Placed between the blocks 54 and 59 is an aligning member or bearing member in the form of a ball 58 which is adapted to engage the spherical seats 55 and 51. The parts are adjusted so that there is a close running fit between the bearing 53 and the spherical seats, and this construction which constitutes an aligning means of my invention holds the adjacent ends of the shafts 20 and 2| in alignment. If either of the shafts is not positioned with its axis along the axis A-A, there may be a relative swinging action produced when the parts rotate. This action is referred to as a pivotal movement as distinguished from a rotational movement such as occurs between certain parts in the apparatus, and the element 2| may be said to be pivotally supported relative to the coupling means. In view of the fact that the coupling member 29 is slidably and rotatably supported by the sleeve 23, any swinging action which occurs must take place between the coupling member 29 and the shaft 2| or the parts associated therewith. Therefore, if "there is any disali'gnment between the shafts 20 and 2| a swinging action will occur around the center of the ball 58 with the result that the blades 42 may swing back and forth, as indicated by the arrow 60. It will be noted that a line passing vertically through the center of the ball 58 bisects the blades 42 so that the arc of swinging of the blades 42 is bisected by this line which extends through the center of the ball 58 which may be indicated as k3 in Fig. 2. The inward and outward movement of the blades 42 is therefore reduced to a minimum with the result that clearances between the various parts may also be reduced to a minimum.

Referring again to Fig. 1, it will be noted that a control means in the form of a switch box 65 is suitably supported adjacent the thrust plate 36. This switch box 65 has an engageaole means or push button 66 which is engaged by the thrust plate 36 just prior to the time that the flange 49 engages the shoulder 50. When the thrust plate engages the button 66 and depresses same, a control switch 61 is opened. This control switch Bl, as shown in Fig. 1 is connected to a wire 68 which extends to the motor I, and to a Wire 89 which extends to a transformer or other source of energy ll]. A wire H is extended from the transformer H! to the motor When the switch 6'! is opened, the motor II is deenergized. For the purpose of enabling the apparatus to be started, at which time it is well understood there is a driving torque which is higher than the normal operating torque, I provide a shunt circuit which includes a wire 13 which shorts out the switch 61. This wire 13 includes a switch 14 which when closed completes the shunt in the circuit around the switch 61. The wire 69 includes a main starting switch 15 which must be closed in order to supply electrical energy to the motor II. By closing the switch 15 and the switch 14, current is supplied to the motor l and the fact that the switch 6! may be opened will not disconnect the electrical circuit. When the device has been brought up to normal speed, the switch 61 will be closed and the switch '14 may thereafter be opened. If an abnormal condition should occur and abnormal torque be transmitted through the control device 22, the coupling member 29 and the thrust plate 36 will move in a rightward direction, and the thrust plate will engage the button 66, thus opening the switch 5.?

and shutting down the motor I I.

This. isdone by firstclosing the switch M and.

thereafter closing the switch 75, both of which are shown inFig. '1. This supplies electrical en'- ergy to the motor 9 i and causes same to operate. The rotation is transmitted through the drive shaft 26, the control device 22 and through the will be driven, notwithstanding that an excessive torque must be transmitted through the device of my invention. Itwill, of course, be understood that when the parts are in this position, which is shown by dotted linesiil in Fig. 2, the button 56 hasbeen depressed and the switch 67 has been opened. This, however, does not disturb the supplying of electrical energy to the motor H due to the fact that the shunt circuitfiS is closed by the switch 74. When the parts are operating at normal speeds, the torque gradually reduces to a normal torque, and the spring ii which has been compressed during the trans.- mission of the excessive torque gradually removes the coupling member 29, as shown by full lines in the drawings in Fig. 1. This will move the thrust plate 36 from contact with the button 66 and the switch 57 will be closed. At this time the operator may open the switch 1 5 which opens the shunt circuit I3, and electrical energy which em ergizes the motor H must be supplied through the switch 6?. h V s As long as operating conditions remain normal, the device will continue to operate until the operator desires to shut same down. This may be done by opening the main switch ?5. If at any time during the operation of the apparatus something occurs which increases the driving torque, the coupling member 29 will commence to move in a rightward direction as indicated by the arrow 33 of Fig. 2. If this torque increases to such an extent that some damage may occur, this being predetermined and being taken into consideration when the adjustable nut 39, which controls the compression of the compression spring 4?, is adjusted, the coupling member 29 will move sufficiently in the direction of the arrow 33 to cause the thrust plate 35 to engage and depress the button 86. This will open the switch 6?" and thus deenergize the motor H. In this manner any injury to the motor or other parts will be prevented, since excessive torque which must be transmitted if the driven means is to be operated under abnormal conditions will automatically move the parts in order to deenergize the motor. r a V During the starting of the apparatus'and when the switches M and 75 are closed, if there were a rigid connection between the drive means and the driven means, considerable shock might be transmitted. By use of my invention, however, this shock is eliminated due to. the factthat the compression spring ilwill yieldand thus'absorb the shock instead of transmitting itthrough the apparatus to the driven means. Q

If any disalignment exists or occurs between the shafts 2i and 2!,the driven shaft 21 is free to swing around the center of the ball 58; as previ-,

ously pointed'out, and this swinging action merely causes the blades @Zto swing back and forth, as indicated'by the arrowiifi in Fig. 2. Although not shown in the drawings, enough clearance will be left between the blades 32 and G3 to allow .free

longitudinal movement between these parts. 7 g

This form of my invention incorporates all of the features thereof and is the preferred form.

of my invention: which is to be used when all of the advantages are desired and when it is to be used between a drive and a driven shaft which must be coupled together, asdisclosed in Figs. 1and2. a

As I have explained heretofore, it is not neces sary to'employ each {and every feature ofmy invention; For example, in-Fig. 5 I have shown a form of my. invention which incorporates only the flexible coupling features and shock absorbing features.-. The form of my inventiondisclosed in Fig.5 is essentially a shock absorber and the flexible coupling features therefore may be fully eliminated if desired; It will be notedthat' various parts shown'in Fig. 5 are equivalent to the parts shown in Fig-.2 except that they are elongated in order that, the coupling ZQgmay;

have a longertraveland the spring may compress to a larger extent. This form of my invention may be very useful in rolling mills where a considerabie strain is brought to pass when ta piece of material to be rolled isplaced in the rolling mill, which may be the driven means of the combination. shown in Fig. 5 are equivalent to the parts shown in Figs. 2 to if inclusive, similar numerals are em- It will be,

ployed on the corresponding parts. seen from an inspection of Fig. 5 that when a shock is imposed which creates an excessive torque, thecoupling member 29 will move in'the direction of the arrow 330i this'figure, thus ab sorbing the shock and not transmitting same to the drive device, and vice versa, if shock'or sud elusive. In this form of my invention shown in Figs. 6 may, the numeral 86 represents a shaft which extends outwardly from the hous- In view of the fact that the parts,

ing of the driven means which maybe any type of apparatus as pointed out .in connection with the formoi my invention shown in Figs. 1 to 4 inclusive.- This shaft 8% is equivalent; to the or body 88.; 1 This outer sleeve 88 is journaled on the inner sleeve B'Land cooperating between these parts is a cam means or connecting means which is generally designated by the numeral 89.

The cam means in this type of my. invention isv threads 9| fitting between helical channels pro vided between the square threads 60. Formed as a part of the body or sleeve 88 is a cylindrical projection 92 which projects outwardly beyond the inner sleeve 81 and which is internally threaded at 93. Threadedly supported in the end of this extension 92 is a shoulder in the form of an adjustment member or adjustment nut 94, which byrotation relative to" the extension 92 may be adjusted into'diiferent positions therein.

This nut 94 constitutes but one form of adjustable shoulder. which may be employed in my invention. Placed within this nut 94 is a bearing 95 which is engaged by the outer end of a compression spring 96., The "inner end of this compression spring 96 engages an end shoulder 98 of the inner sleeve 81. The purpose of the spring 96 is to retain the parts in the positions disclosed in Fig. 6. Secured to the inner face 99 of the body 88 is a friction plate ..I00. This friction plate I has an inner annular portion IOI which projects inwardly a sufficient distance to engage "the inner face I02 of the sleeve 81,'in order to act as astop against which the spring 96 pulls the friction plate I00. 7

Rigidly secured to the body 88 is a pulley member I05 around which a belt means or equivalent I06 is extended for driving the control means of my invention in a. direction indicated by the arrow I01 of Fig. 7. The threads 90 and-9| are formed so that a rotation of the body 88 relative to the sleeve 81 in a direction indicated by the arrow I01 will advance the body 88 in a direction indicated by the arrow I09 of Fig. 6. However, under normal operating conditions such a movement of these parts does not occur because the spring 96 resists relative movement between the parts 81 and 88. The adjustable nut 94 is adjusted so that a certain amount of torque may be transmitted from the body 88 tothe sleeve 81. When the torque required to drive the body 88 exceeds this predetermined value, the body 88 will rotate relative to the sleeve 81 and the body 88 will move in a direction indicated by the arrow I09 until it has moved a sufiicient distance for the end of the thread 90 to engage a suitable shoulder H0, at which time the body 88 has a positive driving engagement with the sleeve 81. Under operating conditions the apparatus will shut down before this positive drive is established, this occurring by reason of the thrust plate I00 engaging a shut-off button I I I; but during the starting of the apparatus this positive drive may be utilized as pointed out in connection with the form of my invention disclosed in Figs. 1 to 4 inclusive, and may be operated by the circuit disclosed diagrammatically in Fig. 1.

In this form of my invention the flexible coupling feature is not utilized since it is not necessary. The drive shaft is not in alignment with the driven shaft, but is spaced therefrom and may be connected thereto by belts, chains or gears as desired. The shock absorbing features are utilized due to the presence of the compression springs 96.

From the foregoing description of the three forms of my invention it is quite apparent that the principle of my invention may be embodied in various structural forms. I therefore do not wish to be limited to the details of construction disclosed in the drawings of this application and described in the specification, but wish my invention to be broadly construed in accordance 'with the advance which I have made in the art and in accordance with the appended claims.

I claim as my invention:

1. In a device of the class described, the combination of: a drive element; a driven element; coupling means by means of which a driving engagement is established between said elements; means whereby a relative rotational movement between one of said elements and said coupling means causes an axial movement of said coupling means; and means whereby one of said elements is pivotally supported relative to said coupling means.

2. In a device of the class described, the combination of: a drive element; a driven element; coupling means by means of which a driving engagement is established between said elements; means whereby a relative rotational movement between one of said elements and said coupling means causes an axial movement of said coupling means; positive drive means whereby a positive driving relationship is established between said elements when. a predetermined rotational movement between said coupling means and the said element has occurred; and means whereby one of said elements is pivotally supported relative to said coupling means.

3. In a-device of the class described, the combination of: a drive element; a driven element; coupling means by means of which a driving engagement is established between said elements; means whereby a relative rotational movement between one of said elements and said coupling means causes an axial movement of said coupling means; means for determining the amount of torque which is transmitted through said elements before relative rotation occurs; and means whereby one of said elements is pivotally supported relative to said coupling means.

4. In a device of the class described, the combination of: a drive element; a driven element; coupling means by means of which a driving engagement is established between said elements; means whereby a relative rotational movement between one of said elements and said coupling means causes an axial movement of said coupling means; means for determining the amount of torque which is transmitted through said elements before relative rotation occurs; positive drive means whereby a positive driving relationship is established between said elements when a predetermined rotational movement between said coupling means and the said element has occurred; and means whereby one of said elements is pivotally supported relative to said coupling means.

5. In a device of the class described, the combination of: a drive element; a driven element in substantial alignment therewith; coupling means through which said drive element drives said driven element; connecting means for drivably connecting said coupling means to said drive element and to said driven element; said connecting means producing an axial movement of said coupling means when a relative rotational movement between said coupling means and one of said elements occurs; and pivotal means connecting the other of said elements to said coupling means.

6. In a device of the class described, the combination of a drive shaft; a driven shaft substantially in alignment therewith; a coupling member slidably and rotatably mounted on one of said shafts; means-for producing axial movement of said coupling, member when same rotates relative to said shaft on which said coupling member is rotatable; means drivably connecting the other of said shafts and said coupling member; and means for yieldingly resisting relative movement between said coupling member and said shaft on which same is slidably and rotatably I 7 said shafts is established when a predetermined mounted;

7. In a device of the class described; the com bination of: a drive shaft; a driven shaft substantially in alignment therewith; a coupling member slidably and rotatably mounted on one of said shafts; means for producing axial movement of said coupling member when same rotates relative to said shaft on which said coupling member is rotatable; means drivably connecting the other of said shafts and said coupling member; means for yieldingly resisting relative movement between said coupling member and said shaft on which same is slidably and rotatably mounted; and aligning means for retaining the ends of said shafts substantially in axial alignment.

8. In a device of the class described, the com-' bination of: a drive shaft; a driven shaft substantially in alignment therewith; a coupling member slidably and rotatably mounted on one of said shafts; means for producing axial movement of said coupling member when same rotates relative to .said shaft on which said coupling member is rotatable; means drivably connecting the other of said shafts and said coupling member; means for yieldingly resisting relative movement between said coupling member and said "shaft on which same is slidably and'rotatably mounted; and positive drive means whereby a member is rotatable; means drivably connecting the other of said shafts and said coupling'member; means for yieldingly resisting relative movement between said coupling member and. said shaft on which same is slidably and rotatably mounted; aligning means for retaining the ends of said shafts substantially in axial alignment; and positive drive means whereby a positive driving connection between said coupling member and movement has occurred between said coupling member and one of said shafts. l

' 10. In a deviceof the class described, the combination of: a driveshaft; a driven shaftsubstantially in alignment therewith; a' coupling *m'ember slidably and rotatably mounted on one of said shafts; means for producing axial movement of said coupling member when same rotates relative to said shaft on which said coupling memher is rotatable; means'drivably connecting the f other of said shafts and said coupling member; and means operable between said coupling member and oneof said shafts for yieldingly resisting relative movement between said coupling member and said shaft on which same is slidably and the other of said shaftsand said coupling member; means operable between said coupling member and one of said shafts for yieldingly resisting relative movement between said coupling member and said shaft on which same is slidably and rotatably mounted; aligning means for re-' taining the ends of said shaft substantially in axial alignment; and positive drive means whereby a positive driving connection between said coupling member and said shafts is established when a predetermined movement has occurred between said coupling member and one of said shafts.

GUGLIELMO TREMOLADA. 

